Inking mechanism with multiple-point control for doctor blade

ABSTRACT

An inking mechanism of a printing machine has a doctor for the duct roller adjustable by set screws spaced apart along the doctor which are individually and selectively rotatable to adjust the doctor by a crank-driven reciprocable carrier through the medium of individually actuatable coupling devices between the carrier and the screws. The coupling devices, each of which comprises an electromagnetically operable engaging member and a toothed wheel or rack operating the related set screw, are controlled by a clock pulse emitter including switch contacts movable by the drive crank at the two dead points of the carrier movement, the switch contacts being wired in circuit with the electromagnets and selector switches.

ilnite tates Ptent Greiner et ai. Sept. 2, 1975 INKING MECHANisM WITH 2,183,720 12/1939 Lougee et al 101/366 x MULTHPLE POINT CONTROL FOR 2,392,706 1/1946 Taylor et al. 101/365 2,497,648 2/1950 Worthington. 101/365 DOCTOR BLADE 2,902,927 9/1959 Ross 101/365 [75] Inventors; Harry Greiner, Offenbach-Main; 9 8/1961 Jordanm /68 Ben cappel, ()ff b h Bi b 3,110.254 11/1963 Davis 10l/365 Alfred Born, Offenbach Main. 3,144,046 8/1964 Seesselberg 137/551 j 3,466,517 9/1969 Leenhouts 318/18 w l Hartung Offenbach 3,488,030 1/1970 Hulme 61 al. 101 /365 UX mgfr'ed Schuhmannt 3,702,587 11/1972 Lee 101 207 Offenbach-Main, all of Germany [73] Assignee: Roland Oiisetinaschinenfabrik primary Reed Fisher Faber & Scmelcher Attorney, Agent, or Firm-Hane, Baxley & Spiecens Offenbach-Main, Germany 22 Filed: Oct. 1, 11973 Appl. No: 402,021

Related U.S. Application Data 5 7 ABSTRACT An inking mechanism of a printing machine has a doctor for the duct roller adjustable by set screws spaced apart along the doctor which are individually and selectively rotatable to adjust the doctor by a crankdriven reciprocable carrier through the medium of individually actuatable coupling devices between the carrier and the screws. The coupling devices, each of which comprises an electromagnetically operable engaging member and a toothed wheel or rack operating the related set screw, are controlled by a clock pulse emitter including switch contacts movable by the drive crank at the two dead points of the carrier movement, the switch contacts being wired in circuit with the electromagnets and selector switches.

3 Claims, 9 Drawing Figures INKING MECHANISM WITH MULTIPLE-POINT CONTROL FOR DOCTOR BLADE This application is a continuation-in-part of application Ser. No. 206,089, filed Dec. 8, 1972, now abandoned.

The invention relates to a device on an inking mechanism for printing machines for adjusting the doctor in relation to the duct roller by means of a plurality of set screws arranged along the doctor and acting upon it, which are intermittently couplable through remotely controllable engaging devices with a reciprocally movable carrier, for the purpose of their rotation.

Such devices serve, especially in multi-color printing machines, the purposes of making it possible to effect adjustments to the inking mechanism or mechanisms from a central position, for example from the delivery or a coordinating table. The possibility of short and reproducible adjustment distances is a prerequisite for the usability of such adjusting devices.

In German Pat- No. 1,241,840 a device is disclosed in which two pawls, each allocated to a set screw, are suspended on a reciprocally movable first carrier which is couplable with a second, constantly reciprocally moving carrier by means of remotely controllable adjusting devices. A further magnetically-operated engaging element is provided for the engagement of one or the other pawl according to choice so as to vary the direction of rotation of the set screws. This element actuates the pawls of all set screws in common, so that in one forward and return movement of the carrier the set screws can be rotated only in one direction. This is a constructionally complex device in which it is necessary firstly, for the set screws which are to be rotated clockwise right, to be actuated and only then for those which are to be rotated counter-clockwise to be actuated, or vice-versa. A device which leaves the sequence of actuation of the set screws to the discretion of the printer would be much more advantageous and much quicker acting.

Furthermore, with the device disclosed in German Pat. No. 1,241,840 it is difficult to permit any clearly reproducible adjusting distances of the screws. The angles of rotation of the screws and thus their adjusting distances are dependent upon the time duration in which the adjusting devices are actuated and thus upon the speed of rotation of the carrier drive. Moreover, the moment of actuation of the adjusting devices is not equal to the moment of becoming effective of the adjustment, so that it is difficult to reproduce adjustment distances if only for this reason. Additional problems associated with the adjusting distance occur in the actuation of the pawls.

[t is an object of the invention to provide a device which is constructionally as simple and stable as possible, while avoiding the disadvantages of already known devices, and which permits rotating the set screws for the adjustment of the doctor by small and clearly reproducible angle steps.

The invention solves the problem in that the operation of coupling and uncoupling of each of the set screws with and from the carrier is controllable by a clock pulse emitter which is stepped in synchronism with the reciprocally movable carrier. The synchronisation of the coupling operation with the carrier movement guarantees that the set screws are displaced by a clearly defined and reproducible angle of rotation on actuation of the coupling operation. The speed of the clock pulse emitter can be predetermined and synchronized with the speed of the carrier, but it is the simplest solution if the clock pulse is tripped directly by the re ciprocally moved carrier.

According to the invention each engaging device has one single remotely operable engaging member which is movable firstly into and then out of engagement with a toothed segment for reversible movement during one forward or return movement of the carrier. The toothed segment can be a fully formed toothed wheel which is keyed on the shank of a set screw in each case. It can however also be a rack, the reciprocating movement of which is convertible into rotating movement by a following toothed wheel. However, the toothed segment in no way has to be secured directly on the set screw actuating the doctor. Rather in kinematic reversal it can be connected with a rotatable but axially nondisplaceable nut in which the set screw, secured against rotation, is axially displaceable. The tooth form of the toothed segment is preferably symmetrical and the tip of the engaging member which comes into contact with the toothed segment is preferably made in tooth form with corresponding flanks. This ensures that equal conditions exist for both directions of movement and the wear on the tooth flanks is slight. Thus, with the sim plest means the object is achieved of displacing the set screws acting upon a doctor, in precisely defined step sizes. This step-by-step adjustment is also logically usable in the adjustment of the quantity regulation of pump inking mechanism known per se. The engaging member can be moved mechanically, by an electromagnet or by a pneumatically or hydraulically operated piston.

The course of the movement, for example of a magnet-operated engaging member-movement into the engagement position, maintenenance of engagement dur ing the forward or return movement of the carrier, movement out of the engagement position, reversal of the carrier is expediently here controlled by electric switch elements. However, other control circuits known in the art can likewise be used.

According to the invention, the toothed segment is followed by an overload clutch which in every case avoids excessive pressing of the set screw on the doctor and consequent damage, for example, in the case of incorrect actuation. Such an overload clutch offers greater reliability in this connection than, for example, an electric limit switch. The overload clutch is expediently so arranged that in the case of overload the toothed segment does not move in relation to the engaging member.

In a development of the invention, the clock pulse emitter comprises at least one first switch contact, actuated approximately in the one dead point position of the carrier, and at least one :second switch contact operated approximately in the other dead point position of the carrier, and with each engaging member there is associated at least one selector switch in series before the switch contacts, which permits the tripping of the bringing of the engaging member into engagement by the switch pulses emitted by the switch contacts optionally in the one or the other dead point position. This arrangement ensures that every engaging member can be switched in every dead point position of the carrier and thus the respective set screw can be rotated by the fixed angle in the clockwise or counter-clockwise direction according to choice. The selector switch constitutes a directing device which has the effect that the bringing of the engaging member into engagement with the toothed segment takes place on the one occasion during the one dead point position of the carrier, and on shifting of the directing device, in the other dead point position of the carrier. The course of movement of the engaging member is maintained here. Only the beginning of the course of movement is displaced. The use of two switch contacts in each case in place of one single switch contact in each dead point position has only circuitry consequences and does not affect the principle.

In an important aspect of the invention, a counter interrupts the transmission of switch pulses after a selectable number thereof. The series-connection of a counter provides the advantage that the respective set screw can be adjusted by any desired multiple of the angle of rotation achievable in one stroke of the carrier, in one course of action if necessary. This possibility has special advantages when the printer effects a coarse pre-setting according to a proof at the beginning of a printing task.

According to the invention, the carrier is driven by a crank drive which is independent of the printing machine. A drive which is independent of the printing machine is stationary. Moreover, the occurring accelerations and inertial forces of a crank drive can be seen in the dead point positions. The reciprocating movement can naturally also be generated by electromagnets, hydraulically or pneumatically.

An especially expedient embodiment of the invention is obtained when the switch contacts of the clock pulse emitter are stationarily arranged and operable by the crank. By variation of the crank length the stroke of the carrier can be varied in known manner. The angle position in which the switch contacts are actuated remains uninfluenced thereby. According to the invention, the switch contacts are formed as reed switches which are actuated in each case in a specific angle position of the crank by a magnet rotating with the crank. Reed switches are relatively cheap and therefore preferable. However, magnetic field-dependent resistors, diodes or Hall effect generators could also be used as contactlessly operating switch contacts. Formation of the switch contacts as light interrupters would have advantages inasmuch as the moment of switching can be determined precisely by the use of calibrated slots.

An embodiment of the invention by way of example will be explained in the following description with reference to the accompanying diagrammatic drawings, wherein:

FIG. 1 shows a lateral elevation of a device according to the invention;

FIG. la shows an enlarged detail of the device shown in FIG. 1;

FIG. 2 shows a view of the device, partially in section along the line IIII in FIG. 1 on a larger scale;

FIG. 3 shows a view of the drive of the carrier of the device with four switch contacts;

FIG. 3a shows a view of the drive of the carrier of the device with two switch contacts;

FIGS. 4 and 5 each show a block circuit diagram of the controlling of an engaging member by two switch contacts;

FIG. 6 shows a logic diagram of the controlling of an engaging member by four switch contacts; and

FIG. 7 shows a block circuit diagram of the controlling of a plurality of engaging members by four switch contacts.

The thickness of the ink film on the duct roller 1 of an inking mechanism (not shown further) is determined according to FIG. 1 by the position of a doctor 2 which can be pressed more or less against the duct roller 1 by a plurality of set screws 3 arranged along the duct roller 1. Thus, regulation of the ink film over the length of the duct roller 1 is possible. Each set screw 3 is mounted for displacement in the axial direction in frame parts 4, 5 which are fixed to the inking mechanism. The displacement is effected by rotation of the set screw 3, which is provided on its periphery with threading which cooperates with a threaded bore in the frame part 4. Secured on the set screw 3 is a toothed wheel 6. In the frame parts 4, 5, a carrier 7 is displaceably mounted which can be set in a reciprocating motion as shown in FIG. 3 by a crank drive 8. On the carrier 7 there are secured solenoids 9 the cores of which are formed as engaging members 10. A solenoid 9 and an engaging member 10 is allocated to each set screw 3. The engaging members 10 are pressed by compression springs l l, which bear on the one hand on the carrier 7 and on the other on a projection 12 of the solenoid core, into a position in which they are not in engagement with the respective toothed wheels 6 of the set screws 3. Conversely, each of the engaging members 10 is in engagement with its associated toothed wheel 6 when the associated solenoid 9 is electrically energized.

Carrier 7, as shown in FIG. 3, is driven by a crank drive 8. The crank 13 of the drive is driven by a geared motor 14 and carries a permanent magnet 15 which switches reed switches 16, 17, 18 and 19 approximately in the two dead point positions of the carrier 7. The reed switches 16 to 19 are arranged on a disc 20 secured on the motor housing, which disc can be rotated slightly after slackening a screw 21.

The control of the movement of the engaging member 10 in the course of a forward or return movement of the carrier 7 will be explained with reference to the block circuit diagrams according to FIGS. 4 to 8. The arrangement according to FIGS. 4 and 5 comprises two switch contact pulsers of a clock pulse emitter, of which in each case one switch contact pulser 23 is actuated approximately in the one and a second switch contact pulser 24 is actuated approximately in the other dead point position of the carrier 7 (see also FIG. 341). By actuation of the selector switch 25 in FIG. 4, the course of movement of the engaging member 10 for a set screw 3 is preselected. The switch contact pulser 23 then trips a switch element 26 and causes the solenoid 9 to be energized, moving member 10 into engagement with wheel 6. The switch element 26 at the same time alerts a second switch element 28 and a third switch element 29. On arrival of a switch pulse as a result of operation of the switch contact pulser 24 (shown in chain lines), the second switch element 28 is finally actuated. Thus, the alerted third switch element 29 is actuated, which resets the selector switch 25 and the switch elements 26 and 28, whereupon the solenoid 9 is deenergized and drops out again. The toothed wheel 6 according to FIG. 3 was rotated by one tooth in the counter-clockwise direction. FIG. 5 shows the same block circuit diagram as FIG. 4. Here only the selector switch 30 was actuated. Accordingly, the switch contact pulser 24 instigates the energization of the solenoid 9 while the switch contact pulser 23 permits the solenoid 9 to drop out again. In this case, the toothed wheel 6 was rotated according to FIG. 3 by one tooth in the clockwise direction.

' The arrangement according to FIG. 6 comprises four switch contacts 16, 17, 18 and 19. By actuation of the selector switch 31 in FIG. 6 the tripping of a first switch element 32 by the switch contact pulser 17 (see also FIG. 3) is prepared. The switch element 32 actuates the solenoid 9 and prepares for the actuation of a second switch element 33. At the same time, the equivalent of a switch pulse from the switch contact pulser 17 is fed from switch element 32 to a counter 34. On arrival of a switch pulse from the switch contact pulser 18, a switch element 33 causes it to transmit a pulse to switch element 32 which is reset and the solenoid 9 switches off. The operation is repeated until the counter 34, after a selectable number of switch pulses of the switch contact pulser l7, restores selector switch 31 which makes switch elements 32 and 33 insensitive to pulses from the switch contact pulsers. If selector switch 35 had been actuated instead of switch 31, then the switch contact pulsers 19, 16 instead of switch contact pulsers would determine the course of control. In the former case, the toothed wheel 6 of the set screw 3 was rotated in the counterclockwise direction and in the latter case in the clockwise direction.

While the switches and switch elements of FIG. 6 can take many forms, a specific embodiment of the circuitry will now be described. It will be assumed that positive logic is used. Selector switches 31 and 35 each comprise a set-reset flipfl0p having a set input, a reset input and an output. Each set input is connected to its respective set pulse source which can be a manual switch connected to a voltage source for manual selection of direction of rotation of the screws or to a programming controller which emits appropriately timed pulses. The reset inputs of both flip-flops are connected to the output of present counter 34.

Since each of the switch contact pulsers is the same, only switch contact pulser 19 will be described. The pulser comprises a single-pole single-throw reed switch whose movable contact is connected to a voltage source V and whose fixed contact is the output which is also connected to one end of a grounded resistor R. Thus, whenever the switch is open the output is at ground and whenever the switch is closed the output is at voltage V. Hence, a momentary closing and opening of the reed switch causes the emission of a pulse from the output.

Switch element 32 comprises a set-reset flip'flop having a set input, a reset input and an output. The set input is connected to two-input OR-circuit 01. The first input of OR-circuit O1 is connected to the output of two-input AND-circuit A1, whose inputs are connected respectively to the outputs of selector switch 31 and switch contact pulser 19. The second input of OR- circuit 01 is connected to the output of two-input AND-circuit A2, whose inputs are connected respectively to the outputs of selector switch 35 and switch contact pulser 17. The reset input is connected to the output of switch element 33. The output of the flip-flop is connected to preset counter 34 and solenoid 9.

Switch element 33 comprises two-input OR-circuit 02 whose output is the output of the element 33. The first input of the OR-circuit O2 is connected to the output of three-input AND-circuit A3, whose inputs are connected respectively to the outputs of selector switch 31, switch contact pulser 16 and switch element 32. The second-input of the OR-circuit O2 is connected to the output of three-input AND-circuit A4 whose inputs are connected respectively to the outputs of selector switch 35, switch contact pulser 18 and switch element 33.

Preset counter 34 comprises a conventional presettable down counter which is preset to a desired count by operation of appropriate preset switches or the like. After the desired number is preset into the counter, each pulse (actually a negative giving transient) that is received at the input of the counter from switch element 32 decrements it by one. When the count reaches zero a pulse is emitted from the output of the counter to the selector switches.

Solenoid 9 can comprise a conventional solenoid whose coil has one end grounded and the other end connected to a power amplifier whose input is connected to the output of switch element 32.

FIG. 7 shows a block circuit diagram for several engaging members. The arrangement again comprises four switch contact pulsers ll6, l7, 18, 19 in accor dance with FIG. 3. On actuation of the selector switches 31, 31' and 31", according to FIG. 6, the switch contact pulsers 17, 18 determine the course of control and all solenoids 9, 9 and 9" are actuated so that the respective toothed wheel 6 is rotated in the counter-clockwise direction in the same way as in the arrangement according to FIG. 6. On actuation of the selector switches 35, 35 and 35" the switch contact pulsers l9, 16 come into action and the course of control takes place as explained above. It appears from the description that the printer can rotate any desired number of adjusting screws in the clockwise direction and at the same time any desired number of adjusting screws in the counter-clockwise direction, by operating the corresponding selector switches, in order to adjust the ink film thickness in the axial direction of the duct roller 1. At the same time, the printer can preselect the magnitude of the rotation by appropriate setting of the counters 34, 34' and 34".

According to FIG. 1a, each toothed wheel 6 is followed by an overload clutch 40. This consists of a disc 41 secured on the toothed wheel 6 and freely rotatable therewith on the set screw 3 and of a disc 43 arranged fast in rotation but axially displaceably on the set screw 3 by means of a key 42. The opposite faces of the discs 41, 43 are toothed for better adhesion. and are pressed against one another by a spring 44 which bears upon a setting ring 45 secured on the set screw 3. A further setting ring 46 secured on the set screw 3 prevents deviation of the toothed wheel 6. The torque transmittable by the overload clutch 40 is determined by the force of the spring 44 and can be varied by displacement of the setting ring 45.

What is claimed is:

1. In a printing machine having an inking mechanism which includes a doctor and a duct roller, apparatus for adjusting the doctor in relation to the duct roller comprising: a plurality of set screws; threaded means for rotatably supporting said set screws along the length of the doctor for acting thereon; a plurality of toothed elements; means for drivably connecting each of said toothed elements to a different one of said set screws; a plurality of solenoid finger means for engaging said toothed elements wherein a single solenoid means is assigned to each of said toothed elements; single carrier means for carrying each of said engaging means operatively opposite a different one of said toothed elements; means for reciprocatingly driving said carrier means between first and second limits along a line parallel to a line defined by the locations of said toothed elements, said means for rcciprocatingly driving said carrier means includinga rotary source of power, a crank connected to said rotary source of power and a crank drive connecting said crank to said carrier means whereby the rotational motion of said rotary source of power is converted to a reciprocating motion of said carrier; means for sensitizing selected solenoid finger means for energization; and energizing means operative at selected ones of said limits for energizing the selected sensitized engaging means, said energizing means comprising a magnet on said crank, at least two magnetically actuated pulse generators adjacent the path of travel of said crank and positioned so as to generate pulses when said carrier is in the region of each of said limits, and means for utilizing such pulses to energize the selected sensitized solenoid finger means during the travel of said carrier between said limits in such a way that the solenoid means are energized during selected directions of the travel of said carrier to provide bidirectional adjustment of the doctor.

2. The apparatus of claim 1 further comprising a plurality of overload clutches, each of said overload clutches connecting a different one of said toothed elements to its associated set screw, and comprising a pair of opposed discs, one being connected to a toothed element and the other connected to the associated set screw for transmitting torque from the toothed element to the associated set screw and means for controlling the friction between the faces of the discs and consequently the maximum amount of torque that is transmittable.

3. The apparatus of claim 1 further comprising means for counting the pulses generated by at least one of said magnetically actuated pulse generators and means for preventing the utilization of such pulses to energize any solenoid finger means after said counting means has counted a predetermined number of such pulses. 

1. In a printing machine having an inking mechanism which includes a doctor and a duct roller, apparatus for adjusting the doctor in relation to the duct roller comprising: a plurality of set screws; threaded means for rotatably supporting said set screws along the length of the doctor for acting thereon; a plurality of toothed elements; means for drivably connecting each of said toothed elements to a different one of said set screws; a plurality of solenoid finger means for engaging said toothed elements wherein a single solenoid means is assigned to each of said toothed elements; single carrier means for carrying each of said engaging means operatively opposite a different one of said toothed elements; means for reciprocatingly driving said carrier means between first and second limits along a line parallel to a line defined by the locations of said toothed elements, said means for reciprocatingly driving said carrier means including a rotary source of power, a crank connected to said rotary source of power and a crank drive connecting said crank to said carrier means whereby the rotational motion of said rotary source of power is converted to a reciprocating motion of said carrier; means for sensitizing selected solenoid finger means for energization; and energizing means operative at selected ones of said limits for energizing the selected sensitized engaging means, said energizing means comprising a magnet on said crank, at least two magnetically actuated pulse generators adjacent the path of travel of said crank and positioned so as to generate pulses when said carrier is in the region of each of said limits, and means for utilizing such pulses to energize the selected sensitized solenoid finger means during the travel of said carrier between said limits in such a way that the solenoid means are energized during selected directions of the travel of said carrier to provide bidirectional adjustment of the doctor.
 2. The apparatus of claim 1 further comprising a plurality of overload clutches, each of said overload clutches connecting a different one of said toothed elements to its associated set screw, and comprising a pair of opposed discs, one being connected to a toothed element and the other connected to the associated set screw for transmitting torque from the toothed element to the associated set screw and means for controlling the friction between the faces of the discs and consequently the maximum amount of torque that is transmittable.
 3. The apparatus of claim 1 further comprising means for counting the pulses generated by at least one of said magnetically actuated pulse generators and means for preventing the utilization of such pulses to energize any solenoid finger means after said counting means has counted a predetermined number of such pulses. 